So, this is a bit of an obscure hint, as it's pretty limited, but if anyone uses a Tascam interface, like the US-122 series or the US-144, for recording or output, here are some usability tips.

Make sure the unit firmware and OS X drivers are up to date.

Sometimes it seems like the unit won't receive enough power. There is a very simple fix for this: Unplug your unit from the USB port and switch Phantom power to Off. Plug the unit back into your Mac, and once it's powered up, then turn on Phantom power. Everything should stay fine.

It seems that on more recent Macs (Unibody, and some pre-Unibodies) that Apple's power manager doesn't like to give too much power to a single USB port. By keeping the Phantom power off when plugging it in, the computer doesn't know the full power required, and is more than willing to give the unit all the power it needs when the switch is on. Others online have suggested a powered USB hub, and indeed this works, but for my purposes, I want to use the unit away from an outlet.

I've tested this with a Tascam US-122mkII. However, the US-122L, US-122, US-144mkII, US-144L and US-144 are all similar. The US-100 should follow for the same rules, but also doesn't require as much power to begin with.

I've had no driver issues running 10.6.2 and using driver version 2, with device firmware version 2.01. All the updates are available at the Tascam site. I'm currently using a Unibody 13" MacBook Pro (Jun 09 introduction), and have confirmed this with the front and back USB port. Testing on my iMac, the same rules apply.

Hmm, I have mixed feelings about this. The amount of power a USB device may draw from a USB port is part of the USB specification (either 100mA or 500mA). So if a device draws more power than the host computer is willing to provide, then either the device or the host is deviating from the specs. In either case, this /might/ cause hardware damage. This might be a design fault, or a defect.

In any case, using a USB hub might offer some protection to your MacBook. It's cheaper to replace than a MacBook MLB :)

Yeah, that's what I thought at first when I was reading other posts online about the issue. However, System Prefs reports everything as normal, and older Macs and PC's seem to have no problems. That's why I've concluded it's a Power Manager issue. OS X warns you if something tries to draw to much power from a port, so far I haven't seen anything bad.

In order to provide phantom power (usually 48V) for a microphone from the much lower voltage that the USB port provides, there will be what's called a DC-DC inverter. This will feed into quite a good sized capacitor to make sure there is no noise or ripple on the supply to the microphone.

In all likelihood what you are seeing when you plug the unit in with phantom on, is quite a surge when the inverter powers up feeding a discharged capacitor. When added to the switch-on surge from the other supply smoothing in the unit, makes Power Manager complain. I would see this as quite normal behaviour, although it has to be said, not a marvellous design. I wouldn't worry, as if there really was too much current being drawn at any time, rest assured Power Manager would tell you about it.

To be honest, I like to plug these sort of devices in and then power-up the Mac.